Wilwood 120-15735 Powerlite-ST Four-Piston Radial Mount Disc Brake Caliper

The Wilwood Powerlite-ST is a high-performance four-piston radial mount brake caliper engineered for rally, circle track, and off-road competition applications. Starting at just 2.5 pounds, this caliper delivers an exceptional strength-to-weight ratio with a low-profile forged aluminum body built to withstand elevated operating temperatures. Wilwood's exclusive Thermlock pistons provide an additional thermal barrier, insulating the caliper body and brake fluid from high rotor temperatures during sustained hard use.

Stress-Flow Forged Construction:

The Powerlite-ST body is manufactured using Wilwood's stress-flow forging process, which re-aligns the metal's grain structure to follow the contour of the caliper rather than interrupting it as straight billet machining does. Combined with an FEA-generated radial transition design, this eliminates steps and shoulders between the piston housing and the caliper bridges—significantly increasing resistance to deflection and caliper separation under heavy braking loads.

Key Features:

• Four-piston radial mount design — simplifies service and provides two planes of adjustment for precise rotor alignment when used with bracket kits
• Thermlock pistons — thermally insulate the caliper from high rotor temperatures for consistent pedal feel
• 7912-type brake pad supported by Quick-Clip top-loading pad retainers — eliminates the need for a bottom pad support step, allowing closer hub mounting on small-wheel and small-rotor applications
• Compatible pad radius matches rotor diameters from 9.45 in (240 mm) to 11.75 in (298.5 mm); fits inside many 13.00 in (330 mm) wheel applications
• Quick-Clip pad retainers — enable fast pad changes without caliper removal; compatible with the full range of Wilwood sport and competition pad compounds
• SRS stainless steel bridge plates — eliminate bridge wear from pad gouging, prevent pad rattle, and dampen vibration harmonics that contribute to brake squeal
• Internal fluid passages — no external tubes required for a clean, compact installation
• Four-corner bleed screws — ensure thorough air evacuation and allow the caliper to be mounted in any of four positions
• Bracket kit compatible — bracket kits (sold separately) include radial mount bracket, studs, locknuts, and alignment shims for installation in place of most lug-mount calipers

The Powerlite-ST delivers proven race technology in a lightweight, versatile package suited for a broad range of performance and competition brake builds.